Sea Cows Dugongs and Manatees: Sirenia

Sirenians have been hunted by humans for food, hides, and bone, a fact that has endangered a number of their species. Steller's sea cow lived for just a few decades before hunting caused its extinction. Manatees and dugongs help balance the marine ecosystem by recycling nutrients in sea grass beds and keeping the plants in a continual state of growth. Without them, the biodiversity, variety, of marine life would be in danger.

Manatees are being closely studied by scientists in hopes that their immune systems can provide clues as to how humans can fight cancer. Because their immune systems, which protect against disease, are very powerful, doctors are looking for tips on how to boost human immune systems. Specifically, they are studying a manatee population that has become infected with papillomavirus (pap-ih-LOH-mah-vye-rus), a virus that develops into cervical cancer in humans. The manatees became infected in the wild and seem to fall victim to cancers as a result. Researchers study tumor tissue and blood samples taken from the infected population, which live in a rehabilitation tank at the Harbor Branch Oceanographic Institution.